public class JavaSE81 {
    public static void main(String[] args) {
/*        String s = "hello";
        String s1 = s.toUpperCase();//全部变大写
        System.out.println(s1);
        String s2 = s1.toLowerCase();//全部变小写
        System.out.println(s2);*/

/*        char[] str = {'h','e','l','l','o'};
        //数组转为字符串
        String s = new String(str);
        //字符串转为数组
        char[] str1 = s.toCharArray();*/
        String s = String.format("%d年%d月%d日",2024,8,1);
        System.out.println(s);
    }
}
